[libdc1394-devel] Re: ieee1394 problem in DMA mode

[Justin H. <he...@cs...>]

I've confirmed this exact same problem, and the solution.  We are 
running both sony and point grey cameras off of several linux boxes, 
each with >1 gig memory (dual processor systems)  After adding the 
kernel option mem=512M, DMA capture started working.  Before that, the 
dma routines would return black images.

-justin

 > FROM: David Ergo
 > DATE: 10/07/2002 01:07:49
 > SUBJECT:  [libdc1394-devel] Re: ieee1394 problem in DMA mode
 >
 >
 >
 > Thank you Dan for your help, but I tested and the problem doesn't come
 > from a bus reset.
 >
 > After many tests, I found the conditions to have this unstable
 > configuration :
 > - PC with 1 GB RAM (I suppose that more RAM will have same effect)
 > - AND High Memory Support enabled in the kernel (4GB but I suppose that
 > 64GB will be the same)

 > I suppose this is a problem in the DMA routines or in the Memory Mapped
 >I/O. But I don't known if it's in libdc1394, in ieee1394 kernel modules
 > or in the kernel itself...
 > Could the libdc1394 & ieee1394 developpers check this please ?
 >
 >The temporary workaround is to have less than 1GB RAM or to disable High
 > Memory Support (but then you can't use the full GB RAM but only 896MB).

 > David